1. Field of the Invention
The present invention relates generally to orthopedic braces and, in particular, to orthopedic knee braces.
2. Description of the Related Art
Osteoarthritis is a degenerative joint disease that results in chronic pain in an affected joint when the joint is statically or dynamically loaded. In an affected knee joint, osteoarthritis pain is often caused by an unbalanced loading on the medial or lateral compartment of the knee, which can reduce the clearance space between the condyles of the femur and tibial plateau. When there is increased pressure between the femoral and tibial surfaces in an affected compartment of the knee joint, and particularly dynamic pressure, cartilage degeneration can occur at the contact surface producing pain in the joint.
Orthopedic knee braces are commonly applied to the leg to treat osteoarthritis in the knee. Such braces typically include an upper support portion for securing to the upper leg of the wearer, a lower support portion for securing to the lower leg, and one or more hinge assemblies pivotally interconnecting the upper and lower support portions. In a two-sided knee brace, a hinge assembly is located at each side of the knee when the brace is worn. A condyle pad is typically located between each hinge assembly and side of the knee.
Knee braces of the type described serve to reduce osteoarthritis pain in the knee joint by applying a three-point load to the leg. A force is applied to the side of the knee opposite the affected compartment by causing the adjacent condyle pad to forcibly contact the side of the knee. This is typically accomplished by increasing the thickness of the adjacent condyle pad or by moving the pad closer to the knee using a jackscrew or other means. Alternatively, a force is sometimes applied opposite the affected compartment of the knee by means of an adjustable force strap which extends around the leg in a helical fashion from the upper support portion to the lower support portion. In either case, counteracting forces are applied to the leg in the medial/lateral plane above and below the knee on the side of the affected compartment by the upper and lower support portions. The resulting three-point load on the leg serves to reduce osteoarthritis pain in the knee joint by reducing the load in the affected compartment of the knee.
While such knee braces have proven effective in relieving osteoarthritis pain in the knee joint, the upper and lower support portions of such braces lack sufficient adjustability for optimal fit on various leg shapes and for various loads to relieve osteoarthritis pain. The upper and lower support portions are typically relatively rigid and are not adapted to conform to the leg shape of the wearer. As a result, such braces are often bulky, uncomfortable, and ill-fitting. In addition, when such braces are adjusted to apply a force to the knee or to fit the leg of a patient, stress is generated in the hinge assemblies of the knee braces. This stress causes wear on the components of the hinge assemblies and, in extreme cases, can result in binding of the hinge assemblies.
Accordingly, it is a principle object and advantage of the present invention to overcome some or all of these limitations and to provide an improved orthopedic knee brace and hinge assembly therefor.
In a preferred embodiment, the present invention provides an orthopedic knee brace including an upper support portion, a lower support portion, and medial and lateral hinge assemblies pivotally interconnecting the upper and lower support portions. The upper support portion includes an upper leg cuff for positioning over the front of the thigh of the wearer and medial and lateral support arms extending from the upper leg cuff to the medial and lateral hinge assemblies. The lower support portion includes a lower leg cuff for positioning over the calf of the wearer and medial and lateral support arms extending from the lower leg cuff to the medial and lateral hinge assemblies. An adjustment device is located between each leg cuff and support arm on one side of the brace.
The adjustment devices allow adjustment of the knee brace to fit a variety of different leg shapes. Once fitted, the adjustment devices allow further adjustment of the brace to apply a three-point load to the leg to relieve osteoarthritis pain in the knee. The hinge assemblies allow medial and lateral articulation of the support arms as the brace is adjusted, allowing the brace to conform to the shape of the leg of the wearer. Because the hinge assemblies allow medial and lateral articulation of the support arms, adjustment of the knee brace does not generate stress in the hinge assemblies, which can otherwise cause excessive loading and wear and tear on the hinge assemblies during repeated flexions and extentions.
Moreover, a knee brace incorporating one or more hinge assemblies having features and advantages in accordance with the invention can be made more compact and light-weight for a given amount of knee bracing. A knee brace incorporating one or more hinge assemeblies having features and advantages in accordance with the invention can also be made with both medial and lateral support arms, without compromising the desired compact size and while greatly reducing the likelihood of the knee brace to bind at one or more of the hinges when used on a leg having a varus or vulgus shape. Thus, more reliable bracing is provided.
In accordance with one embodiment the present invention provides a hinge assembly for an orthopedic knee brace having upper and lower support arms. The hinge assembly includes a hinge plate and first and second gear members pivotally connected to the hinge plate. The first gear member is coupled for rotation with the upper support arm and has an articulation surface adjacent a surface of the upper support arm. The second gear member is coupled for rotation with the lower support arm and has an articulation surface adjacent a surface of the lower support arm. The hinge assembly allows articulation of the upper and lower support arms on the articulation surfaces in a plane substantially perpendicular to a plane of rotation of the first and second gear members.
In accordance with another embodiment the present invention provides a hinge assembly for an orthopedic knee brace having upper and lower support arms. The hinge assembly includes a hinge plate and first and second gear members pivotally connected to the hinge plate. The first and second gear members have intermeshing gear teeth on adjacent perimeters thereof. The first gear member is coupled for rotation with the upper support arm and has an articulation surface adjacent a surface of the upper support arm. The second gear member is coupled for rotation with the lower support arm and has an articulation surface adjacent a surface of the lower support arm. The hinge assembly allows articulation of the upper and lower support arms on the articulation surfaces in a plane substantially perpendicular to a plane of rotation of the first and second gear members.
In accordance with another embodiment a hinge assembly is provided for an orthopedic knee brace having upper and lower support arms. The hinge assembly includes a hinge plate and first and second gear members pivotally connected to the hinge plate. The first and second gear members have mating gear teeth on adjacent portions thereof. The first gear member is coupled for rotation with the upper support arm and has an articulation surface adjacent a surface of the upper support arm. The second gear member is coupled for rotation with the lower support arm and has an articulation surface adjacent a surface of the lower support arm. The hinge assembly allows articulation of the upper and lower support arms on the articulation surfaces while maintaining coplanarity of the first and second gear members.
In accordance with another embodiment the present invention provides an orthopedic knee brace having an upper leg cuff mountable above the knee of a wearer and a lower leg cuff mountable below the knee of the wearer. Upper and lower support arms extend from the upper and lower leg cuffs to a hinge assembly disposed between the upper and lower leg cuffs. The hinge assembly comprises a hinge plate and first and second gear members pivotally connected to the hinge plate. The first and second gear members have intermeshing gear teeth on adjacent portions thereof. The first gear member is coupled for rotation with the upper support arm and has an articulation surface adjacent a surface of the upper support arm. The second gear member is coupled for rotation with the lower support arm and has an articulation surface adjacent a surface of the lower support arm. An adjustment device is coupled to at least one of the support arms for allowing adjustment of an angle or amount of torsion between the support arm and associated leg cuff. The hinge assembly allows such adjustment while maintaining relative coplanarity of the first and second gear members.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.